Improvement in metal strings for pianos



PATENT OEEIcE.

J. B. THOMPSON, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN METAL STRiNGS FOR PIANOS, 8L0.

Specification forming part of Letters Patent No. 26,304, dated November 29, 1859.

To all whom "it may concern Be it known that I, J. B. THOMPSON, of the city of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a new and useful Improvement in Stringed Musical Instruments; and I do hereby declare that the following is a full, clear, and exact description of the same.

My invention consists in the employment for the strings of piano-fortes and other stringed musical instruments of hardened and tempered steel wire, such wire being less brittle and having greater tenaciousness of sound and producing more brilliant tones in its vibrations than the steel music wire heretofore used, which has always been made hard by repeated drawing in a cold state without annealing.

In the manufacture of the wire I anneal as often as is necessary between the successive operations to prevent the frequent breakages which unavoidably occur when the drawings are repeated without annealing, and when the wire is drawn to the proper size I harden it by passing it continuouslyin a longitudinal direction first through a furnace of suitable construction and then through a bath of cold water or Oll, and afterward temper it by passing it through a bath of heated oil, which may be so arranged that the wire passes directly to it on its way from the hardening-bath first mentioned. By this system of hardening and tempering I am enabled to bring every part of the wire to the same heat and to give it a perfect homogeneousness of structure or texture.

The strings made of this kind of wire are applied to piano-tortes and other stringed instruments in the same manner as the wirestrings heretofore used.

hat I claim as my invention, and desire to secure by Letters Patent, is-

The employment for the strings of piano fortes and other musical instruments of hardened and tempered steel wire, as herein described.

, J. B. THOMPSON.

Witnesses:

MILTON S. SLEEPER, J ERRY S. BARRACLIFF. 

